Inflatable penile implants depend upon closed hydraulic systems to maintain a desired pressure in a pressure chamber for extended periods of time. In U.S. Pat. No. 4,353,360, an inflatable penile implant is described which includes a pressure chamber which is a non-distensible cylindrical chamber. When the pressure chamber is pressurized, it becomes rigid and the penis assumes an erectile state.
The components of the hydraulic system of inflatable penile implants are made of the suitable materials and are designed to operate reliably under conditions which normally might be encountered. There are, however, occasions in which the pressure within the pressure chamber may greatly exceed that for which the components were designed. For example, when the implant and its inflated pressure chamber are accidentally bent or squeezed, a much higher pressure than normal can be generated within the hydraulic system. Such increased pressures can cause damage to the hydraulic system components and cause the implant to fail.
In the Finney U.S. Pat. No. 4,622,958, issued accumulator which increases in volume to absorb and compensate for any increased pressures that might otherwise damage the hydraulic system components.
Another problem which can accompany the use of inflatable penile implants is getting the right size inflatable implant into some patients. Although the surgeon carefully takes measurements and selects the proper size implant for a patient, with some patients it is still difficult to maneuver the implant into the corpora cavernosum. With such patients it would be helpful if the implant could be shortened even slightly for insertion into the corpora without impairing its function.
Still another problem that can occur with inflatable implants is tissue encapsulation which can cause the implant to become constrained or shortened so that it cannot reach its full length. It would be helpful to have an implant the functioning of which would not be impaired even if the implant became constrained in length.